JP5415136B2 - Portable computer and computer program - Google Patents

Description

  The present invention relates to a technique for improving the convenience of an external display device connected to a portable computer, and more specifically, recognizes the pixel size of the connected external display device and changes settings for the internal display and the external display. Regarding technology.

  Notebook type portable computers (hereinafter referred to as notebook PCs) use an internal display built in the main body of a casing in a mobile environment. However, since the internal display has a small screen size, it cannot be said that the workability is sufficiently good. In order to compensate for this, the notebook PC can be used by connecting an independent external display to an external terminal attached to the housing. In a so-called dual display environment in which an internal display and an external display are used simultaneously, a simultaneous display mode (also referred to as a clone mode or a mirror mode) that displays the same screen on the external display and the internal display, an external display and an internal display A display method called an extended display mode (also referred to as an expansion mode) is adopted in which the display is handled as one desktop screen and the windows can be moved to each other.

  In the simultaneous display mode, one image developed in VRAM (Video Random Access Memory) is displayed on the external display and the internal display. The maximum pixel size of the display matches the screen size. The pixel size of the normal image is generated to match the screen size of the internal display. Therefore, when the pixel size of the external display is larger than the pixel size of the internal display, an image smaller than the screen size is displayed on the external display. At this time, it is possible to correct the image according to the ratio between the pixel size of the external display and the pixel size of the image, but the corrected image is an image that matches the pixel size of the external display. Loss of clarity compared to.

  Further, since the external display is attached to and detached from the notebook PC body, the internal display is set as the primary display and the external display is set as the secondary display. The window display position, which is one of the arguments set in the API that the application program calls to create a window, has the upper left corner of the display area of the primary display as the origin coordinate. The first window is displayed on the primary display.

  Patent Document 1 discloses, for a plurality of display devices connected to a computer, preferably information on the number of colors, resolution and synchronization frequency, information on power management function and / or screen saver function, and which one is used as a primary display device. Setting information including at least one of the information on whether to perform the setting is stored as a profile, and various settings are made simultaneously on a plurality of display devices by selecting the profile, thereby enabling the setting and setting of the display function. A technique for easily performing switching is disclosed.

International Publication No. 2003-093967

  2. Description of the Related Art In recent years, notebook PCs having a simple function mainly for connection to the Internet, called NetBook (registered trademark) or UMPC (Ultra-Mobile PC), have been developed. UMPC has functions intermediate between those of conventional notebook PCs and PDAs, but the hardware and software to be implemented are simplified compared to conventional notebook PCs, and the functions are provided at low cost. It is characterized by. Hereinafter, in this specification, a notebook PC having a simple function is referred to as a UMPC in contrast to a notebook PC having a conventional function. On the other hand, an OS such as Windows (registered trademark) or Linux (registered trademark) is also installed in UMPC, and various application programs (hereinafter simply referred to as applications) can be used.

  The user may wish to use the UMPC in a state close to a desktop computer. The internal display built in the housing of the UMPC is not suitable for opening a large number of windows on the desktop screen at the same time because the screen size or the maximum pixel size is small. UMPC is equipped with a USB terminal as standard, and various USB devices can be connected. Since an external display is also provided as a USB device, it is possible to connect an external display to a UMPC that is not provided with an external display terminal.

  As one of USB devices, there is a function expansion device called a USB port replicator. If a USB port replicator is always connected to a plurality of peripheral devices on a desk, it is possible to use a plurality of peripheral devices by simply connecting the USB port replicator to the USB port of the UMPC when using the UMPC in an office environment. It becomes possible. Since the external display connected to the UMPC is used to compensate for the narrow working range of the internal display, it often has a larger screen size or maximum pixel size than the internal display. When an external display with a large pixel size is connected to the UMPC, in extended display mode, the user can make the external display the primary display so that the display on which the first window of each application is displayed is the external display. There is hope to use as.

  In the simultaneous display mode, there is a desire to display a large image corresponding to the pixel size on the external display. In order to use an external display as a main screen when an external display having a large pixel size is connected in this way, the setting of the primary display is changed according to the display mode, or the image image developed in the VRAM is changed. You need to change the pixel size. Also, before using the UMPC in a mobile environment, it is necessary to restore the setting to use the internal display as the main screen. It is a burden on the user to perform these operations manually each time the USB port / replicator is attached / detached.

  Accordingly, an object of the present invention is to improve the convenience of an external display connected to a portable computer. A further object of the present invention is to reduce the burden on the user when connecting an external display having a large pixel size to a portable computer.

  The portable computer according to the present invention is configured such that an internal display is attached to a housing and an external display can be connected to an external terminal. The interface between the external terminal and the external display need not be particularly limited. Further, the video chip for transferring the image image to the external display may be built in the portable computer or provided outside the portable computer. The present invention is particularly effective in an environment where the connection between the external terminal and the external display is frequently detached.

  In response to detecting the connection of the external display, the portable computer compares the pixel size of the external display with the pixel size of the internal display. Then, the display mode is determined as either the simultaneous display mode or the extended display mode. When the pixel size of the external display is larger than that of the internal display, it is more convenient for the user to use the external display as the main screen in the simultaneous display mode or the extended display mode. Thus, if the display in the extended display mode is determined and the external display pixel size is larger than the internal display pixel size, the portable computer sets the external display as the primary display.

  Therefore, since the first window created by the application can be an external display, the user does not need to move the window by a drag operation from the internal display to the external display as the main screen. At this time, the pixel size set for the external display may be changed to the pixel size of the external display. By adding this operation, even when the system cannot read the pixel size from the identifier of the external display when the external display is connected, the pixel size of the external display can be surely set.

  When the display in the simultaneous display mode is determined, it is desirable that the portable computer sets the pixel size set for the internal display to be larger than the pixel size of the internal display and smaller than the pixel size of the external display. By doing so, a screen larger than the pixel size of the internal display can be displayed on the external display, and the display area is enlarged. Preferably, when the pixel size set for the internal display matches the pixel size of the external display, it is possible to prevent deterioration in image quality due to correction for matching the image with the screen size of the display.

  Further, the external display may be set as the primary display in the simultaneous display mode. By doing so, the tool bar is also displayed on the external display, so the workability on the external display is improved. In addition, the burden on the video chip can be reduced if the internal display is displayed in a so-called panning mode in which only part of the image is displayed within the screen size in the simultaneous display mode. A video chip with a low function can be employed. When determining the display mode, a screen for the user to select the display mode may be displayed on the internal display, or the display mode setting is stored in advance as a default value without user intervention. You may make all settings with. The external display can be connected to a portable computer via a USB port replicator with a built-in graphics processing unit. In this case, the external display is frequently attached to and detached from the portable computer, but the burden on the user regarding the setting of the display is small. When it is detected that the connection of the external display is disconnected from the portable computer, the portable computer recognizes the display mode immediately before the disconnection and uses the portable computer in the mobile environment according to the recognized display mode. After that, the internal display can be used without any trouble.

  According to the present invention, the convenience of an external display connected to a portable computer can be improved. Furthermore, according to the present invention, the burden on the user when connecting an external display having a large pixel size to the portable computer can be reduced.

It is a block diagram which shows the outline structure which shows a mode when a portable computer (UMPC) is connected to a USB port replicator. It is a figure which shows the structure of the software which implement | achieves the setting method of the display concerning this invention. It is a flowchart which shows the procedure which sets a display when a USB port replicator is connected. It is a flowchart which shows the procedure which resets the setting of a display when a USB port replicator is removed. It is a figure explaining the display method of the image image in simultaneous display mode. It is a figure explaining the display method of the image image in extended display mode.

  FIG. 1 is a block diagram showing a schematic configuration showing a state when the UMPC 10 is connected to the USB port replicator 51. In the UMPC 10, a central processing unit (CPU) 11, a main memory 13, a hard disk drive (HDD) 15, a video chip 19, an input / output device 21, a USB controller 23, and a BIOS ROM 27 are connected to a system bus 17. ing. The video chip 19 is connected to a VRAM 20 and a liquid crystal display (LCD) 21 which is an internal display built in the housing of the UMPC 10. The video chip 19 creates an image image in the bit map format based on a drawing command by a program executed by the CPU 11 and stores it in the VRAM 20, and the data is displayed on the LCD 21 together with the horizontal synchronization signal, the vertical synchronization signal, and the clock signal. Send to. The LCD 21 conforms to the SVGA standard and has a maximum horizontal × vertical pixel size (also referred to as maximum resolution) of 800 × 600 dots.

  The HDD 15 stores a program related to the present embodiment shown in FIG. A USB terminal 25 is connected to the USB controller 23. The configuration of these UMPCs 10 is well known except for programs stored in the HDD 27. Various USB devices can be connected to the USB terminal 25. In FIG. 1, a USB port replicator 51 is connected. Connected to the USB port replicator 51 as a peripheral device of the UMPC 10 are a speaker 55, a microphone 57, an LCD 59 as an external display, and a USB device 61 such as a keyboard or a mouse.

  The USB port replicator 51 is provided with a converter for converting the USB protocol and a controller for controlling each peripheral device. FIG. 1 shows only the video chip 53 and the VRAM 54 necessary for explaining the present invention. Show. Similarly to the video chip 19, the video chip 53 creates an image image in a bit map format based on a drawing command by a program executed by the CPU 11 and stores it in the VRAM 54. It is sent to the LCD 59 together with the synchronization signal and the clock signal. The LCD 59 conforms to the XGA standard, and has a horizontal × vertical pixel size of 1024 × 768 dots, which is larger than the LCD 19.

  Note that FIG. 1 is merely a simplified description of the main hardware configuration and connection relationships related to the present embodiment in order to describe the present embodiment. In addition to those mentioned in the above description, many devices are used to configure the UMPC 10. However, they are well known to those skilled in the art and will not be described in detail here. A person skilled in the art also arbitrarily selects a plurality of blocks described in the figure as one integrated circuit or device, or conversely, a block is divided into a plurality of integrated circuits or devices. Is included in the scope of the present invention. In addition, the types of buses and interfaces connecting the devices are merely examples, and other connections are included in the scope of the present invention as long as those skilled in the art can arbitrarily select them. It is.

  FIG. 2 is a diagram showing a software configuration for realizing the display setting method according to the present invention. A display operation application (hereinafter referred to as an operation program) 101 is an event-driven program that runs on the OS 105 to perform a central function for setting a display. The operation program 101 receives an event related to the display setting from the system queue of the OS 105, sets the primary display for the video chip 19 or the video chip 53, and sets the display mode for the user. Provide a screen for the video chip 19 and 53 to set the pixel size. The operation program 101 is resident in the main memory 13 when the OS 105 is executed.

  Here, the primary display means that when multiple displays are connected to one computer system, it displays the state in which the BIOS is operating after the power is turned on, or displays a tool bar at the bottom of the screen. Or a display that provides a reference for coordinates when an application program calls an API to display a window. The primary display is set to only one display selected from a plurality of displays, and all other displays are treated as secondary displays even if there are a plurality of other displays. When the UMPC 10 has a primary display and a secondary display, images can be displayed on the two displays in either the simultaneous display mode or the extended display mode.

  The OS 105 is not particularly limited in the present invention, but this embodiment will be described using Windows (registered trademark) as an example. The video driver 107 acquires identification information (EDID) from the LCD 59 and sets the pixel size, bit depth, refresh rate, and the like in the video chip 53, and data between the OS 105 and the video chip 53. It is a program that controls the transfer. The USB port driver 109 is a program that recognizes a USB device connected to the USB terminal 25 and sets the USB controller 23, and controls data transfer between the OS 105 and the USB port replicator 51. The video driver 111 realizes the same function as the video driver 107 with respect to the video chip 19 and the LCD 21.

  The video BIOS 113 is a program for setting the video chip 19 to the simultaneous display mode and displaying on the LCD 21 until the OS 105 starts operating after the power of the UMPC 10 is activated. Note that the software shown in FIG. 2 is stored in the HDD 15 except for the video BIOS 113. The video BIOS 113 is stored in the ROM in the video chip 19.

[Setup steps]
FIG. 3 is a flowchart showing a procedure for setting the display when the USB port replicator 51 is connected. FIG. 5 is a diagram for explaining a method for displaying an image in the simultaneous display mode, and FIG. 6 is a diagram for explaining a method for displaying an image in the extended display mode. In block 201, the UMPC 10 is operating in a mobile environment. When the power of the UMPC 10 is started, the system BIOS stored in the BIOS ROM 27 sets the LCD 21 as the primary, and the OS 105 can display a screen on the LCD 21. The video driver 111 acquires EDID (Extended Display Identification Data) stored in the EEPROM of the LCD 21 and compares it with the values supported by the video chip 19. The video driver 111 then stores the pixel size, bit depth, brightness and refresh on the video chip 19. -Set configuration information such as rate. Configuration information for the LCD 21 is stored in the registry of the OS 105. The video driver 111 sets the video chip 19 to 800 × 600 dots equal to the pixel size of the LCD 21. The OS 105 recognizes that the display area of the display is 800 × 600 dots, and issues a drawing command to the video driver 111 so as to generate an image image of the pixel size. Images that match are displayed.

  In block 203, the UMPC 10 shifts from the mobile environment to the office environment, and the USB port replicator 51 to which the LCD 59 is connected is connected to the USB terminal 25. The USB port driver 109 and the OS 105 that have recognized the connection to the USB terminal 25 by the plug-and-play function obtain configuration information from the USB port replicator 51, set the USB controller 23, and the UMPC 10 and USB port. Establish communication with the replicator 51. Thereafter, when the video chip 53 detects that the LCD 59 is connected to its output port, the video driver 107 obtains the EDID from the LCD 59 and compares it with the value supported by the video chip 53. Configuration information such as pixel size, bit depth, brightness, and refresh rate. Configuration information for the LCD 59 is stored in the registry of the OS 105.

  Here, the video driver 107 sets the video chip 53 to 1024 × 768 dots, which is the same as the pixel size of the LCD 59. Then, the video driver 107 notifies the OS 105 and the operation program 101 that a new display has been connected. The OS 105 issues an enumeration request to the video drivers 107 and 111 to acquire the EDID of the LCD 59 and LCD 21 that are currently connected. In block 205, the operation program 101 obtains the EDIDs of the LCDs 59 and 21 from the OS 105 and compares the pixel sizes of the two displays.

  When the operation program 101 determines in block 207 that the pixel size of the LCD 21 is larger than the pixel size of the LCD 59, the process proceeds to block 208. In this case, since the user does not need to use the LCD 51 as the main screen, the UMPC 10 operates in the simultaneous display mode or the extended display mode according to a well-known procedure. When the operation program 101 determines in block 207 that the pixel size of the LCD 59 is larger than the pixel size of the LCD 21, the process proceeds to block 209.

  In block 209, the operation program 101 displays a pop-up screen on the LCD 21 to allow the user to select the display mode of the LCD 59 in order to use the LCD 59 having a large pixel size as the main screen. The pop-up screen includes radio buttons and input windows for setting the pixel size of the LCDs 59 and 21, setting the primary display, and setting the display mode. When the user selects the simultaneous display mode for the pop-up screen, the operation program 101 calls the API from the OS 105 and sets the pixel size set in the video chip 19 to the pixel size of the LCD 59 in block 211. Request to change to 1024 × 768 dots. As the API, Windows (registered trademark) ChangeDisplaySettingEx can be used, or an API for changing display settings provided by an IHV (independent hardware vendor) can be used.

  The OS 105 sets the pixel size of the video chip 19 to 1024 × 768 dots through the video driver 111 and stores the pixel size of the video chip 19 in the registry. When the pixel size of the video chip 19 is changed from 800 × 600 dots to 1024 × 768 dots, when the OS 105 displays an image on the LCD 21, the display area of the LCD 21 is changed to a size (1024 × 768). 5A, a drawing command is sent to the video driver 111 so as to secure a memory space of that size in the VRAM 20 and generate the image image 301 as shown in FIG. In response to a drawing command from the CPU 11, the video chip 19 generates an image image 301 in the VRAM 20, and sends the image image 301 read from the VRAM 20 to the LCD 21 with a predetermined drive clock. Since the image image 301 is larger than the pixel size of the LCD 21 as shown in FIG. 5A, only the image 307 corresponding to the pixel size or screen size of the LCD 21 is displayed on the LCD 21. The remaining image 305 is out of the display area of the LCD 21.

  An image 305 that is out of the display area of the LCD 21 can be displayed on the LCD 21 by a cursor key or a pointing device scroll operation using the input device 21. A method of displaying only a part of the image on the display having a narrow screen size in this way is called a panning mode. In block 213, the operation program 101 notifies the video BIOS 113 to change to the simultaneous display mode through the OS 105 and the video driver 111. The video BIOS 113 that has received the notification sets the video chip 19 to the simultaneous display mode, and the OS 105 stores the set display mode in the registry. In the simultaneous display mode, the image image 301 supplied to the LCD 21 as the primary display is transferred from the VRAM 20 to the VRAM 54 through the USB controller 23 by the video chip 19 and supplied from the VRAM 54 to the LCD 59 as the secondary display by the video chip 53. Is done.

  Therefore, the LCD 21 and the LCD 59 display the image 307 and the image 303 for the same image image 301, respectively. Since the pixel size of the image image 301 and the pixel size of the LCD 59 match, an image 303 corresponding to the screen size is displayed on the LCD 59. By such an operation, in the simultaneous display mode, the user can work by displaying a window in a wide work area of the entire screen formed by the pixel size of the LCD 59. On the LCD 21, the image 305 is displayed in the panning mode, so that it is difficult for the user to work. However, the overall workability is improved by using the LCD 59 as the main screen.

  In this embodiment, the image is displayed on the LCD 21 in the panning mode. However, the image image 301 can be displayed after being reduced and corrected so as to match the pixel size of the LCD 21. However, since the burden on the video chip 19 increases and the capacity of the VRAM 20 increases, in the case of the UMPC 10, display in the panning mode is desirable. If the pixel size set in the video chip 19 is not changed in the block 211 in the simultaneous display mode, an image 311 matching the pixel size of the LCD 21 is stored in the VRAM 20 as shown in FIG. Since the image is expanded, the image 315 is displayed on the LCD 21 in a state that matches the screen size of the LCD 21.

However, the image 311 displayed on the LCD 59 is smaller than the screen size of the LCD 59. When the image 311 is enlarged and corrected in order to make the image 311 match the screen size of the LCD 59, the clearness of the image is lost. Either block 211 or block 213 may be executed first, but the one that executed block 211 first matches the screen size from the moment the image is displayed on the LCD 59 and displays a clear image. Can be displayed. In block 211, the OS 105 does not necessarily need to match the pixel size set for the video chip 19 with the pixel size of the LCD 59 , and the pixel size set for the video chip 19 exceeds the pixel size of the LCD 21. It is also possible to set the pixel size to be equal to or smaller than.

  When the user selects the extended display mode for the pop-up screen in block 209, the process proceeds to block 215, and the operation program 101 notifies the OS 105 to change the display mode to the extended display mode. The OS 105 stores the changed display mode in the registry, and thereafter recognizes the display area of the LCD 29 and the LCD 59 as a total value of the respective pixel sizes and displays the image when displaying the image. A drawing command is sent to the video drivers 111 and 107 so as to generate image images 351 and 353 corresponding to the area. At this time, the pixel size of the video chip 19 is set to 800 × 600 dots in the block 201, and the video chip 53 is set to 1024 × 768 dots in the block 203.

  In FIG. 6, the image image 351 generated by the video chip 53 is stored in the VRAM 54, and the image image 353 generated by the video chip 19 is stored in the VRAM 20. Since the pixel size of the image image 351 matches the pixel size of the LCD 59 and the pixel size of the image image 353 matches the pixel size of the LCD 21, the LCD 59 and 21 respectively match the screen size. The displayed images 355 and 357 are displayed. In block 217, the operation program 101 calls an API from the OS 105 to set the LCD 59 as a primary display. The OS 105 stores the primary display setting information in the registry.

  Thereafter, the OS 105 displays the tool bar on the LCD 59 and the window display position as an argument to be set in the API CreateWindow that the application calls from the OS 105 in order to create a window is the upper left corner of the display area of the LCD 59 as the coordinate origin. Calculated. Therefore, a window newly created by the application is displayed on the LCD 59. When the state where the LCD 21 is set as the primary display is maintained, the window created by the application is first displayed on the LCD 21. In order to display the window on the LCD 59 having a wide work area, the user must perform a drag operation each time. However, according to the present embodiment, such inconvenience is solved. Depending on the application, the position of the window moved by the drag operation can be stored, and when a new window is generated next time, it can be displayed at the position of the last window. Specifies the display position of the window to be generated in reference to the coordinate origin of the primary display.

  The pixel size of the LCD 59 is set to the video chip 53 in block 203, but on some displays the video driver 107 may not be able to read the pixel size from its EDID. In that case, the pixel size corresponding to the EDID is registered in the operation program 101, and in block 219, the operation program 101 calls the API from the OS 105 to set the pixel size to be set in the video chip 53 to the pixel size of the LCD 59. Request to change to 1024 × 768 dots equal to. Note that the pixel size registered in the operation program 101 needs to be larger than the pixel size of the LCD 21, but does not necessarily match the pixel size of the LCD 59. In block 221, the setting for either the simultaneous display mode or the extended display mode when the USB port replicator 51 is connected ends.

  FIG. 4 is a flowchart showing a return procedure when the USB port replicator 51 is disconnected from the USB connector 25 after the setting of FIG. When the USB port replicator 51 is suddenly removed in block 251 or when the USB port replicator 51 is disconnected based on the normal procedure by the user, the video driver 107 notifies the operation program 101 via the OS 105. To do. In block 253, the operation program 101 confirms the display mode of the UMPC 10 just before the USB port replicator 51 is removed.

  If the previous display mode is the simultaneous display mode in block 255, the process proceeds to block 257 where the operation program 101 calls the API from the OS 105 to set the pixel size set in the video chip 19 to the pixel size of the LCD 21. A request is made to change to an equal 800 × 600 dots, and the process proceeds to block 261. The OS 105 sets the pixel size of the video chip 19 to 800 × 600 dots through the video driver 111 and stores it in the registry. Thereafter, as shown in FIG. 5B, an image image 311 matching the screen size of the LCD 21 is generated in the VRAM 20 and displayed as an image 315.

  When the immediately preceding display mode is the extended display mode in block 255, the process proceeds to block 259, and the operation program 101 calls the API from the OS 105 to set the LCD 21 as the primary display. The OS 105 stores the primary display setting information in the registry and proceeds to block 261. When the power of the UMPC 10 is turned off while the USB port replicator 51 is connected, the LCD 21 is set as the primary display in the system BIOS. Therefore, during the POST (Power Of Self Test), the LCD 21 When the screen is displayed and the OS 105 operates and the operation program 101 further operates, the procedure shown in FIG. 3 is executed to newly set the display.

  In the procedure of FIG. 3, the LCD 21 is maintained as the primary display in the simultaneous display mode, but the LCD 59 may be set as the primary display. By doing so, the user can operate the window because the tool bar is displayed on the LCD 59 which is the main screen. In block 209 of FIG. 3, the pop-up screen is displayed and the user is allowed to perform the display setting operation. However, the display mode setting is determined in advance by default and no user operation is performed. You may be able to complete the display settings. Alternatively, the operation program 101 may store the previously set state immediately before the power of the UMPC 10 is shut down, and the setting may be reproduced next time.

  Further, the example in which the LCD 59 is connected to the UMPC 10 via the USB port replicator 51 with the built-in video chip 53 has been described. However, the present invention is a dual type capable of outputting two data streams to the UMPC 10. A video chip of a mode can be mounted and applied to an external display connected through an interface such as VGA (Video Graphics Array), DVI (Digital Visual Interface), and DP (DisplayPort). It can also be applied to an external display with a built-in video chip.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

10 ... Portable computer (UMPC)
51: USB port replicator 301, 311, 351, 353 ... image 303, 305, 313, 315, 355, 357 ... image

Claims (10)

A portable computer that has an internal display attached to the housing and can be connected to an external display.
Detecting that the external display is connected;
Comparing the vertical and horizontal pixel counts of the external display with the vertical and horizontal pixel counts of the internal display in response to detecting the connection of the external display;
Determining a display mode as either a simultaneous display mode or an extended display mode;
When the display in the extended display mode is determined and the number of pixels in the vertical and horizontal directions of the external display is larger than the number of pixels in the vertical and horizontal directions of the internal display, the external display is set as the primary display. A computer program for executing a process having a step of setting to The process is
The computer program according to claim 1, further comprising the step of setting the logical vertical and horizontal pixel numbers set in the external display to the vertical and horizontal pixel numbers of the external display. The process is
Logic for determining display in the simultaneous display mode and setting the internal display when the number of vertical and horizontal pixels of the external display is larger than the number of vertical and horizontal pixels of the internal display 2. The computer according to claim 1, further comprising the step of reducing the number of vertical and horizontal pixels in the vertical direction and the horizontal direction beyond the number of vertical and horizontal pixels in the internal display to less than or equal to the number of vertical and horizontal pixels in the external display. ·program.   The step of making the number of pixels in the vertical and horizontal directions of the external display equal to or less than the number of pixels in the logical vertical and horizontal directions set in the internal display is set to the number of pixels in the vertical and horizontal directions of the external display. The computer program according to claim 3, comprising a matching step. The process is
5. The computer program according to claim 3, further comprising a step of causing the internal display to display in a panning mode in which only a part of the image is displayed when the display in the simultaneous display mode is determined.   6. The computer program according to claim 3, further comprising a step of setting the external display as a primary display when the display in the simultaneous display mode is determined.   The computer program according to any one of claims 1 to 6, wherein the step of determining the display mode includes a step of displaying a screen for the user to select a display mode on the internal display.   The computer program according to any one of claims 1 to 7, wherein the external display is connected to the portable computer via a USB port replicator with a built-in graphics processing unit. The process is
Detecting that the connection of the external display is disconnected from the portable computer;
Recognizing the display mode of the portable computer immediately before disconnection;
The computer program according to claim 1, further comprising a step of returning the portable computer to a state of being used in a mobile environment according to the recognized display mode. Portable computer with a recording medium storing a computer program according to any of claims 1 to 9.

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